Re: [PATCH V7 4/5] scsi: storvsc: Add Isolation VM support for storvsc driver

[Jakub Kicinski]

On Thu, 3 Feb 2022 15:53:51 -0800 Jakub Kicinski wrote:
> On Mon, 13 Dec 2021 02:14:05 -0500 Tianyu Lan wrote:
> > @@ -2078,6 +2079,7 @@ struct hv_device *vmbus_device_create(const guid_t *type,
> >  	return child_device_obj;
> >  }
> >  
> > +static u64 vmbus_dma_mask = DMA_BIT_MASK(64);  
> 
> This breaks the x86 clang allmodconfig build as I presume those
> involved know by now:
> 
> ../drivers/hv/vmbus_drv.c:2082:29: error: shift count >= width of type [-Werror,-Wshift-count-overflow]
> static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
>                             ^~~~~~~~~~~~~~~~
> ../include/linux/dma-mapping.h:76:54: note: expanded from macro 'DMA_BIT_MASK'
> #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
>                                                      ^ ~~~
> 1 error generated.

Looks like a compiler issue actually, found the discussion now:

https://lore.kernel.org/llvm/202112181827.o3X7GmHz-lkp@xxxxxxxxx/